Endometriosis-associated ovarian cancer: a clinicopathologic review

Endometriosis is a common clinical disorder in women and usually presents with pelvic pain, infertility, or adnexal masses secondary to intracystic hemorrhage with the formation of an endometrioma. Endometriosis shares certain characteristics with malignant neoplasms, and malignant ovarian tumours have been documented in women with endometriosis. Endometriosis-associated ovarian cancer (EAOC) usually occurs in younger women, has favourable outcomes, and appears as either a low-grade tumour of endometrioid cell type or as a clear cell tumour. As it has been suggested that the pathologic features of "atypical endometriosis" may constitute a precancerous state, women with atypical endometriosis may be at an increased risk of developing EAOC. There are no prospective randomized trials assessing treatment regimens for EAOC. Most women receive treatment similar to other epithelial ovarian cancers. However, women with EAOC represent a subgroup of patients that may require different therapeutic options. English-language journals indexed in MEDLINE and PubMed were searched for relevant articles that evaluated the association between endometriosis and ovarian cancer, theories of pathogenesis and transformation, the clinical presentation and pathologic features of EAOC, as well as the treatment options available.